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Commit 51fb80fe authored by Larry Finger's avatar Larry Finger Committed by John W. Linville
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p54usb: Fix to prevent SKB memory allocation errors with 4K page size 



On x86_64 architecture with 4K page size and SLUB debugging enabled, stress
testing on p54usb has resulted in skb allocation failures of O(1) and extreme
page fragmentation. Reducing rx_mtu fixes this problem by reducing the size of
all receive skb allocations to be of O(0). This change does not impact
performance in any way.

Signed-off-by: default avatarLarry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: default avatarJohn W. Linville <linville@tuxdriver.com>
parent d1b29405

drivers/net/wireless/p54/p54common.c

+11 −0
Original line number Diff line number Diff line
@@ -138,6 +138,7 @@ int p54_parse_firmware(struct ieee80211_hw *dev, const struct firmware *fw) 
	u8 *fw_version = NULL;

	size_t len;

	int i;

	int maxlen;



	if (priv->rx_start)

		return 0;
@@ -195,6 +196,16 @@ int p54_parse_firmware(struct ieee80211_hw *dev, const struct firmware *fw) 
			else

				priv->rx_mtu = (size_t)

					0x620 - priv->tx_hdr_len;

			maxlen = priv->tx_hdr_len + /* USB devices */

				 sizeof(struct p54_rx_data) +

				 4 + /* rx alignment */

				 IEEE80211_MAX_FRAG_THRESHOLD;

			if (priv->rx_mtu > maxlen && PAGE_SIZE == 4096) {

				printk(KERN_INFO "p54: rx_mtu reduced from %d "

					         "to %d\n", priv->rx_mtu,

						 maxlen);

				priv->rx_mtu = maxlen;

			}

			break;

			}

		case BR_CODE_EXPOSED_IF: